Hi,
This could be folliculitis or inflammation of the hair follicles which presents as a pimple like lesion with associated itching or pain. It usually resolve on its own and has a tendency to recur. It is important to keep the area clean and dry. Warm compress may also help. Avoid manipulating the lesion to avoid secondary infection. Try to wear nonconstrictive clothing to prevent unnecessary hair removal.
If it still persists, it would be best to have it evaluated by your doctor or have a referral to a gynecologist. Take care and keep us posted.
Do you shave your genital area? If so it might be the result of ingrown hairs. I would go to your gynocologist to get it checked out just in case. Good luck :)